The need for providing continuous lubrication to bearings and other parts subject to frictional engagement with moving parts has long been recognized. Such need is particularly acute in those applications wherein the bearing is directly exposed to severe environments which cause rapid deterioration or wear to the bearing if not continuously lubricated.
Providing proper lubrication to a bearing can in many instances be achieved by simply packing the bearing with grease or oil, and providing one or more seals between the bearing and the external environment. This technique is generally adequate where the structure is not directly exposed to severe external or pressurized environments. However, in applications wherein a bearing seal is exposed to variable pressures such that the external environment pressure may exceed that of the internal lubricant chamber which supplies lubricant to the bearing, the probability of seal failure and consequent bearing damage significantly increases. Also, in applications wherein the protective bearing seal members are directly exposed to chemically abrasive environments, seal deterioration and consequent bearing failure is significantly accelerated.
In such applications, it is desirable to maintain a positive pressure differential between the inside of the lubricant containing chamber for the bearing and the external environment such that the lubricant pressure provides support for the bearing's protective seal against changing environmental back-pressures. Creating such a positive pressure differential across the protective seal also provides self-lubrication of the seal as lubricant seeps past the seal into the external environment, thus protectively coating the seal and shielding it from chemically abrasive external environments.
Various methods for implementing continuous-lubrication structures for addressing the above-described concerns are known in the art. However, in general, such prior art techniques have either been labor-intensive so as to require virtually continuous operator monitoring, or have been fairly complex and expensive and/or have required apparatus designed specifically for one particular lubrication application. For example, one way of providing a continuous positive pressure head to a lubrication chamber is to continuously add lubricant under pressure to the chamber during operative use. Such technique either requires continuous operator presence or automated lubricant-injection apparatus for injecting grease or other lubricant into the lubrication chamber. The problems associated with this approach are further complicated by the fact that the lubricant must often be pumped through small tubes over significant distances before reaching the remotely located lubricant reservoir. In cold weather the lubricant becomes stiff and unmanageable to accurately control.
Another technique for providing a lubrication with a positive pressure head has been to design self-lubricating chambers, generally configured to include a piston or spring-loaded biasing means associated with the chamber such that continuous or preprogrammed pressure is applied to the lubricant within the chamber so as to provide a positive pressure differential across the protective outer seal. Such structures, while performing the desired function, generally require designs that are specifically dedicated to the shape and configuration of each particular lubrication chamber and often require maintenance and lower the reliability of the entire structure. Besides, such structures are generally not practical for accurately maintaining pressure heads through long narrow tubes to remotely located reservoirs.
The present invention provides a simple and highly effective method and apparatus for maintaining a positive lubricant pressure head to a bearing or other structure requiring constant lubrication and to its associated protective seals. The present invention is applicable to lubrication chambers having varied types of lubricants (i.e., oil, grease, etc.), to lubrication chambers of virtually any shape, and can be readily adapted to existing lubrication chambers without costly retrofit expenses for parts or labor.